U.S. District Judge Nina Gershon issued the preliminary injunction against the government, saying it's in the public's interest for the organization to continue receiving federal funding.

ACORN claimed in its lawsuit that Congress' decision to cut off its funding was unconstitutional because it punitively targeted an individual organization.

Gershon said in her ruling that ACORN had raised a "fundamental issue of separation of powers. They have been singled out by Congress for punishment that directly and immediately affects their ability to continue to obtain federal funding, in the absence of any judicial, or even administrative, process adjudicating guilt."

Bill Quigley, the legal director of the Center for Constitutional Rights, which brought the lawsuit on behalf of ACORN and two affiliates, said the decision sends a sharp message to Congress that it can't single out an individual or organization without due process.

"It's a resounding victory for ACORN," he said. "I'd be surprised if the government decides to appeal."

ACORN, or the Association of Community Organizations for Reform Now, describes itself as an advocate for low-income and minority homebuyers and residents in communities served by its offices around the country. Critics say it has violated the tax-exempt status of some of its affiliates by engaging in partisan political activities.

The law that halted ACORN's federal funding took effect Oct. 1 and was extended Oct. 31. It was set to either expire or be extended again on Dec. 18.

ACORN's lawsuit was filed in federal court in Brooklyn and sought reinstatement of the funds. Quigley said millions of dollars in funds should begin to flow again to ACORN next week. The judge said the "public will not suffer harm by allowing the plaintiffs to continue work on contracts duly awarded by federal agencies."

ACORN has been dogged by allegations of voter-registration fraud and embezzlement.

Several of its offices were the subject of an embarrassing hidden-camera sting in which ACORN employees were shown advising a couple posing as a prostitute and her pimp to lie about her profession and launder her earnings. The videos sparked a political uproar, with Republicans trying to use the group's troubles to portray Democrats as corrupt.

The group's lawsuit named the U.S. government, the secretary of Housing and Urban Development, the director of the Office of Management and Budget and the secretary of the Treasury as defendants.

Justice Department spokeswoman Beverley Lumpkin said the agency was reviewing the decision and declined to comment further.

"Today's ruling is a victory for the constitutional rights for all Americans and for the citizens who work through ACORN to improve their communities and promote responsible lending and homeownership," ACORN CEO Bertha Lewis said in a statement.